John a



(No Model.) J. A. EVARTS.

SUSPENSION DEVICE FOR LAMPS.

No. 325,203, Patented Aug. 25. 1885.

iiimu B 30G 61 vazta 351d @1413. nvcnlob, @5 @212,

N. PETERS. Phom-Mhognpher. Wanhmglw'. D. c.

Ururnn Srarns JOHN A. EVARTS, OF MERIDEN, CONNECTICUT, ASSIGNOR TO THE BRAD- LEY 8: .llUB ZAED MANUFACTURING COMPANY, OF SAME PLACE.

SUSPENSION DEVICE FOR LAMPS.

SPECIFICATION forming part of Letters Patent No. 325,203, dated August 25, 1885.

Application filed July 13, 1855.

T ctZZ whom it may concern.-

Be it known that I, JOHN A. l lvAu'rs, of Meriden, in the county of New Haven and State of Connecticut,have invented anew Improvement in Suspension Devices for Lamps, &c.; and I do hereby declare the following, when taken in connection with accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and rep resent, in

Figure 1, a side view of the suspending device; Fig. 2, a top view of the same; Fig. 3, a transverse section through the frame, showing edge view of the disk and the spring which holds the cams in their hearing position; Fig.

1 rotation of the said platelimited, and the plate 4, a transverse section through the frame, showing the stop to arrest the movement of the dish in producing friction upon the drum. This invention relates to an improvement in 5 such partial rotation of the drum in one directhat class of suspending devices in which a spring 1s employed as the power for lifting, and such as used for suspending lamps from the ceiling, so that the lamps may be adjusted to any required elevation. In this class of apparatus the power of the spring is fixed and unchangeable, the spring itself being arranged within or in connection with a drum, so that 0 a chain or cord is wound upon the drum in the lifting operation under the reaction of the spring, or drawn from the drum in lowering the thing suspended, which operation winds the spring. The power of the spring is fixed, 5 while the thing to be suspended is liable to considerable variation-as in the case of a lamp, the suspending device is adapted to receive the various styles of lamps, and these styles vary considerably in weight, or the same fixture is liable to great variation, as by change of shade or change of fount, so that if the thing to be suspended be below a certain weight, the power of the spring, being greater than that certain weight, will raise the fixture, 5 and the highest elevation will be the only resting-point; and, on the contrary, if the thing suspended be heavier than the power of the spring, then the lowest point of the thing suspended will be the place of rest. It is therefore necessary that some auxiliary power (No model.)

be applied between the spring and the thing suspended, whichmust be overcome, either by the spring or thing suspended, before the spring or suspended thing may operate. This auxiliary or intermediate power is usually in the form of friction, applied so that in drawing down or raising the thing suspended the said friction must be overcome; and this friction enables the suspended thing to rest at any desired point.

It is to the frictional appliances to which my invention especially relates; and it consists in a plate adapted to bear upon one end of the drum, or corresponding surface in connection with the drum, the said plate arranged for partial rotation with the drum under frietional contact between the two, the extent of provided with cam-like surfaces to act against corresponding stationary points in the frame i nwhich the drum is supported, so that, under tion, the cam-like action increases the friction between the plate and the drum, and in the opposite direction reduces that friction, as 7 5 more fully hereinafter described.

In illustrating my invention I show it as applied to a drum arranged upon avertical axis, from which two chains extend-one from one side and the other from the opposite side- So over guide-pulleys downward, and to which chains the thing to be supported is attached, and so that as the thin g rises the drum will revolve and wind the two chains thereon; or, the thing susprnded being drawn downward, the two chains will be drawn from the drum, imparting to the drum a rotation which will wind the spring withinit--a common and wellknown construction, and requires but general description.

A B represent the two sides of the frame, united at opposite ends by connections C C, and so as to form a space between the two sides to receive the drum D. The drum is arranged upon an axle, E, in the usual manner, and 95 with the spring within the drum, one end at tached to the drum and the other to the axle, the axle itself being fixed, and so that as the drum is revolved in one direction it will wind the spring, then the reaction of the spring will I00 lGVOlX'B the drum in the opposite direction, in the usual manner.

F is the loop by which the device is suspended, and so that the drum will revolve in ahorizontal plane.

GG are two chains runningfroin the drum one to one side and the other to the opposite sideoverguidepulleys H H, also in the usual manner. On one end of the drum a disk, I, is arranged concentric with the drum, and so as to bearupon that end of the drum. The surface of the drum or of the disk may be provided with a non-metallic surface, a, to increase the friction between the two. The disk is loose upon the axle, and independent of the drum as to its rotationthat is, so that the drum may rotate independent of the disk. On the outside surface of the disk cam or wedge like projections or surfaces 1) are arranged. Preferably two of such cam-like projections are employed and diametrically opposite each other, and so that the said cam-like surfaces may work beneath the side A of the frame, as indicatedin Figs. 3 and 4. The said cams, entering beneath the side A of the frame, act as wedges between the frame and the drum, tending to press the disk I with greater or less force against the end of the drum, accordin gl y as the wedges are forced inward to a greater or less extent. If the wedges be drawn outward, as indicated in Fig. 3, then the pressure of the disk I upon the drum is is reduced; forced inward, as seen in Fig. 4, or as indicated in broken lines, Fig. 3, the pressure of the disk is increased. The arrangement of the cams is in such relation to the drum that as the chains or cords are drawn from the drum, as in the act of drawing down the thing suspended, the tendency is to draw the wedges inward between the frame and the drum, and so as to force the disk hard against the drum. The direction of rotation in drawing down the article is indicated in Fig. 2 by an arrow. The friction between the disk and drum is such that any rotation of the drum tends to impart corresponding rotation to the disk; hence as the drum rotates, as in the act of drawing down the thing suspended, the disk I will rotate accordingly, and draw the wedges beneath the frame A, as indicated in broken lines, Fig. 3, until further movement of the disk be arrested, and will therefore increase the friction from the start of the disk until such arrest. To thus arrest the disk, I provide a stop, d, which may be simply a lug on the disk, to strike, say, one side of the frame A; but I prefer to make the movement of the disk adjustable, and therefore introduce through the stop d an adjusting-screw, 0, adapted to bear against a C01 responding point, f, on the frame A. When, therefore, the stop arrests the further movement of the disk, the wedge like action ceases, and the friction then produced becomes the maximum amount of friction upon the drum, and this friction must be overcome in drawing down the thing suspended; but on lifting the thing suspended the first movement of the drum in rewinding the chains or cords thereon is to return the disk I and withdraw the cams from their hearing, and so as to leave the drum substantially free, and the action of the drum, in rewinding the chains in the drawing up of the thing suspended, will be free from such frictional bearing, but so soon as the thing suspended is left free to bring its weight again upon the drum, then, if the weight begreater than the power of the spring, in descending, the thing suspended will turn the drum until the action of the cam produces a friction so great that the extra weight of the thing suspended is counterbalanced, and will atthat point rest.

To insure the action or engagement of the disk with the drum, a spring, 9, is applied, the tendency of which is to turn the disk so as to force the cams into action; but the spring yields on the return of the drum sufficient to release the frictional bearing of the cams.

The same frictional device may be applied to a drum in any positionsay as upon a horizontal axis, or with a single or more chains or cords. The friction is adjusted by turning the screw 6 so as to make the bearing of the cams greater or less, as occasion may require.

l Vhile I prefer to make the cams as a part of a disk, a portion of the disk may be cut away so as to form a bar, as indicated in broken lines, Fig. 2, the bar oscillating on the axle the same as the disk; but I prefer the disk; as it gives a greater extent of friction than would the bar.

The spring 9 is desirable as preventing the possibility ot'non-action of the cams; but it may be dispensed with, the frictional contact between the disk and the end of the drum be ing generally sufficient to bring the cams into action.

I claim 1. The combination of the supportingframe, axle, and spring-drum with an oscillating bar or plate concentric with the axle between one side of the frame and the end of the drum, said plate carrying a wedge-like cam adjacent to the said side of the frame, substantially as and for the purpose described.

2. The combination of the supportingframe, axle, and spring-drum with an oscillating bar or plate concentric with the axle between one side of the frame and the end of the drum, said plate carrying a wedge-like cam adjacent to the said side of the frame, and an adjusting-screw, substantially as described, and whereby the extent of movement of said plate may be adjusted.

3. The combination of the supportingframe, axle, and spring-drum with an oscillating bar or plate concentric with the axle between one side of the frame and the end of the drum, said plate carrying a wedge-like cam adjacent to the said side of the frame, and a spring between the frame and the said bar or plate, substantially as described, the action of the said spring being to force said cam between the frame and drum.

4. The combination of the supportingframe, axle, and spring-drum, the disk I be tween one side of the said frame and the end of the drum, loose upon the axle and so as to oscillate thereon, and cams b b on said disk, diametrically opposite each other and adjacent to the said side of the frame, substantially as and for the purpose described.

5. The combination of the supportingfra-me, axle, and spring-drum, the disk I between one side of the said frame and the end of the drum, loose upon the axle and so as to oscillate thereon, camsbbon said disk,diametrieally opposite each other and adjacent to the said side of the frame,'and a stop between said frame and disk, substantially as and for the purpose described.

6. The combination of the supportingframe, axle, and spring-drum, the disk I between one side of the said frame and the end screw, 0, on said disk, substantially as described.

7.- I'he combination of the supportingframe, axle, and spring-drum, the disk I between one side of the said frame and the end of the drum, loose upon the axle and so as to oscillate thereon, cams b bon saiddisk, diametrically opposite each other and adjacent gto the said side of the frame, and a spring, 9, between said disk and frame, substantially as described.

JOHN A. EVARTS.

*itncsses:

W. B. BooTH, Cans. A. PALMER. 

